Hydraulic classifying apparatus siphon control



Nov. 1, 1966 v. R. REYNOLDS ETAL 3,282,422

HYDRAULIC CLASSIFYING APPARATUS SIPHON CONTROL Filed Jan. 14, 1963 FIG.1

INVENTORS. VICTOR R. REYNOLDS Y AUGUSTUS W. CUMMINGS,JR.

ATTORNEY.

United A States Patent 3,282,422 HYDRAULIC CLASSIFYING APPARATUS SIPHON CONTROL Victor R. Reynolds, Weston, and Augustus W. Cummings,

Jr., Fairfield, Conn., assignors to Dorr-Oliver Incorporated, Stamford, Conn., a corporation of Delaware Filed Jan. 14, 1963, Ser. No. 251,379 3 Claims. (Cl. 209158) This invention relates {generally tohydraulic classifying apparatus and more particularly to hydraulic classifying apparatus for the sizing and classification of solids which provides automatic control for the discharge of the coarse material from the apparatus through a siphon.

Prior to this invention hydraulic classifying apparatus have been used to size and classify solid material such as ore and other mineral substances. Some of these. hydraulic classifiers employ siphons to remove or discharge the coarse material from the classifier. Normally, a constant supply of prime water was supplied to the siphon at all times in order to maintain the prime of the siphon. It has been found that this constant supply of prime water tended to dilute the concentrated coarse material and thereby reduce the overall efiiciency of the classifier.

It is, therefore, an object of this invention to provide a hydraulic classifier with siphon discharge which automatically controls the supply of prime water to the siphon.

A second object of the invention is to provide a hydraulic classifier with siphon discharge which automatically supplies prime water to the when required and cuts oil the supply of prime water to the siphon when not required.

A third object of the invention is to provide a hydraulic classifier which is automatically and positively controlled to discharge the desired coarse product from the classifier.

A still fiurther object of the invention is to provide a compact and etficient automatically controlled hydraulic classifier to size and classify solids supplied thereto in a liquid solution.

Other objects and advantages of the invention will become apparent as the specification proceeds to describe the invention with reference to the accompanying drawing, in which:

FIG. 1 is a simplified partially schematic representation of a single hydraulic classifier incorporating the hereinafter disclosed siphon automatic control; and

FIG. 2 is a line-line circuit diagram of the control employed in FIG. 1.

In the preferred embodiment the invention is shown and disclosed in relation to -.a hydraulic classifying apparatus which employs the use of .a teeter column wherein conditions of hindered settling are employed. In this type of apparatus the solid material to be divided is supplied into the upper portion of the apparatus as a liquid slurry. In the lower portion of the apparatus an uprising column of fluid is supplied through a constriction area in a direction opposing the supply of the above mentioned liquid slurry with the result that certain particles, which are capable of settling through the uprising flow of fluid in the upper portion of the apparatus, can settle no further than the constriction. With a continuous feed these certain particles will build up above the constriction area and provide a teeter column which will hinder the settling of subsequent particles. coarser particles will then tend to settle through the teeter column while the finer particles and the liquid in the feed tend to rise due to the greater density of the teeter column. Preferably, then the desired product located above and adjacent the constriction area is withdrawn 3,282,422 Patented Nov. 1, 1966 lay the use of a siphon type ejector with the siphon bell located above the constriction area.

In this type of hydraulic classifying apparatus a predetermined rate of water flow is selected to provide a predetermined teeter rate in order to classify particular size particles. Obviously the rate must stay fairly constant in order to obtain a particular product from the classifier. An excess of undesired water would obviously disturb the teeter rate resulting in the discharge of a product which was not contemplated.

In FIG. 1 there is shown only one hydraulic classifier for the sake of simplicity but it is within the scope of the invention to employ a plurality of such units either in series operation or in parallel operation.

Looking now in particular at FIG. 1 the numeral 10 designates a tank into which a liquid slurry of solid material to be classified is supplied thereto by any suitable means such as conduit 12. A constriction plate 14 with orifices 16 therein provides a water chamber 18 at the bottom of the tank. Conduit 20 with valve means 22 therein is provided to supply water to water chamber 18. A valved drain line 24 communicates with upper chamber 26 of tank 10 to afford a means to completely drain the tank 10, if desired. During operation of the hydraulic classifier valv'ed drain line 24 will be shut oil. A launder 28 is provided to collect and carry oil the fine fractions which do not settle in the tank 10'.

A hollow tube 30 open to the atmosphere at the top end projects downwardly into the chamber 26 to a point adjacent the constriction plate 14. ".[he pressure of the denser slurry .at this point will cause water to rise in tube 30 to a point which corresponds to the pressure at the lower end of the tube. A bellows member 32 in open communication with tube 30 expands and contracts in response to the level of liquid in the tube 30. Bellows 32 on expansion or contraction causes switch member 34 to make or hreak contact with contacts 36. Y

To remove the settled product from the tank 10, a siphon system generally denoted by the reference numeral 40 is provided. Siphon system 40 basically consists of a lower pipe section or siphon bell 42, an uprising intermediate pipe section 44 of a diameter smaller than the lower pipe section 42, and a downwardly directed discharge pipe section 46 connected to the upper end of intermediate pipe section 44. Preferably pipe section 46 is smaller in diameter than pipe section 44.

A solenoid operated three-way diaphragm valve 48 is provided to control the discharge of the coarse settled product through discharge pipe section 46. That is, an air inlet line 50 and an exhaust conduit 52 are shown connected to two ports of the valve 48 to either supply vent. or exhaust conduit 5-2.

The

or exhaust air to or from the area surrounding diaphragm member 54 via conduit 55. Member 54 acts to out off flow through pipe section 46 when connected to air supply line 50 land to permit such flow when connected to air In both FIGS. 1 and 2 the solenoid coil for the valve 48 is denoted as 56.

Dilution water and prime water are supplied to siphon bell 42 through conduit 58. Conduits 60 and 62 are provided to supply dilution water and prime water to conduit 58, respectively. The flow of dilution water through conduit 60 is controlled by solenoid operated valve 64 with the solenoid coilin FIGS. 1 and 2 designated as 66. The flow of prime water through conduit 62 is controlled by solenoid operated valve 68 with the solenoid coil designated as 70in both FIGS. 1 and 2.

Located adjacent the peak of siphon system 40, that is, near the top of intermediate pipe section 44 of siphon 40 is a bellows member 72 in open communication with siphon 40 to sense the pressure therein. In normal operation of the siphon bellows 72 will be contracted to the siphon.

due to the negative pressure in the siphon keeping the switch member 76 away from the contacts 78.

Operation Assuming that the tank 14- is filled with water and water is being continuously supplied through conduit and constriction plate 14 at a desired value and assuming further that the solids to be classified are being supplied through conduit 12, the conditions in the tank will gradually build up to provide the desired teeter column. The resulting pressure adjacent the lower end of the tube will force water up the tube 30 and into the interior of bellows 32. Bellows 32 will then expand causing switch member 34 to make contacts 36 thereby energizing the circuit to solenoid valves 48, 64, and 68. Looking at FIG. 2 it can be seen that the making of contacts 36 immediately energizes coils 56 and 66 of solenoid valves 48 and 64. Energization of solenoid valve 48 will place the valve in the position shown allowing the air around the diaphragm member 54 to exhaust to atmosphere through conduit 52 and thereby open discharge pipe section 46. At the same time energization of solenoid valve 64 will open conduit 60 and allow the flow of dilution water to the siphon bell 42 to dilute the solids concen tration so that the coarse settled particles may be readily siphoned.

As shown it is assumed that the siphon is already primed so that the settled material will discharge from the siphon without the addition of prime as water to prime the siphon. Under his condition it can be seen that the negative pressure in the siphon will keep the bellows 72 contracted thereby maintaining switch member 76 away from contacts 78. Solenoid valve 68 will then be deenergized closing off prime water conduit 62.

If at any time during operation of the hydraulic classifier or on start-up the siphon is not primed, bellows 72 will expand due to the higher than desired pressure in the siphon and cause switch member 76 to engage con tacts 78 to energize solenoid valve 68 to allow a flow of prime water to the siphon in order to prime same. This flow of prime water is in addition to the normal flow of dilution water. The flow of dilution water alone can be insufficient to prime the siphon because a low flow rate of water up leg 44 of the siphon can just trickle out the relatively large diameter leg 46 without expelling the air therein. Therefore, an additional flow of water through priming conduit 62 which may preferably be of larger size than dilution water conduit 60 (see FIGURE 1), is provided to ensure a suflicient flow of water through the siphon to prime it. As soon as the siphon resumes proper operation a negative pressure in the siphon will be reestablished causing bellows 72 to contract pulling switch member 76 away from cont-acts 78 thereby deenergizing solenoid valve 68 to stop the additional flow of prime water to the siphon bell 42.

Whenever the pressure adjacent the constriction plate 14, as sensed in the tube 30, drops below a predetermined level, the bellows 32 will contract causing switch member 34 to break contact with contacts 36 and thereby deenergizing the circuit which includes solenoid valves 48, 64, and 68. Solenoid valves 64- and 68 will close oif conduit-s and 62 respectively and solenoid coil 56 will be deenergized causing valve 48 to be rotated to the position where air conduit 50 is in communication with the area around diaphragm 54 exerting an air pressure on the diaphragm to stop the flow of solids within the discharge pipe section 46.

It should be noted that the deenergizing of such circuit lnsures that no water, either prime or dilution is supplied This prevents the undesirable eflfect of upsetting the teeter rate of the column due to an excess of undesirable water being supplied. Thi is especially true when low hydraulic rates are being used to perform the classification.

The herein disclosed control system is preferably electrically controlled but it is within-the scope of the invention to pneumatically or hydraulically control the solenoid valves.

As disclosed diaphragm 54 is operated on an on-oif basis. This is the simplest and most direct means of control. Obviously though other means can be employed to control the discharge of coarse material through the siphon discharge leg 46. An example of other controls which can be employed would be to use an additional pressure sensitive switch responsive to the height of liquid in the tube 30. An inverse modulating type valve would then be substituted for the three-way valve 48. The pressure, dependent on the density at the bottom of the tube 30, sensed by the additional pressure sensitive switch will be relayed to the inverse modulating valve to modulate the flow of coarse particles through the siphon leg 46 in response to the density of the coarse particles adjacent the constriction plate. In other words air in conduit 50 will be supplied in increasing amounts to modulate the diaphragm 54 towards the closed position as the density of the coarse material decreases. Conversly, air will be exhausted in varying amounts from around diaphragm 54 as the density of the coarse material adjacent the lower end of tube 30 increases in order to allow diaphragm to modulate towards the open position.

This new and novel control system provides for positive and automatic control of a hydraulic classifying apparatus which automatically primes the siphon discharge conduit, when necessary, and also prevents undesirable dilution of the settled product whenever the use of prime water is not necessary. This invention further provides a control system which is directly responsive to the condition of the system and is efiicient in operation. Further, the new and novel hydraulic classifying apparatus control insures that no prime water is supplied to the system whenever the system is shut down or is not operating due to low pressure in the teeter column.

Although we have described in detail the preferred embodiment of our invention, we contemplate that many changes may be made without departing from the scope or'extent of our invention, and we desire to be limited only by the claims.

We claim:

1. Hydraulic classifying apparatus comprising: a tank, means supplying solids to be classified into the upper portion of said tank, constriction means in the lower portion of said tank, means adapted to provide a teeter column between said solids supply-means and said constriction means including means supplying a liquid into the lower portion of said tank below said constriction means and providing an upward flow of liquid through said constriction means and said teeter column to accumulate solids of predetermined settling rate adjacent said constriction means, siphon means extending to a point adjacent said constriction means to withdraw said accumulated solids, controllable means to supply prime liquid to said siphon means, controllable means to supply dilution liquid to said siphon means to facilitate the siphoning of said solids, mean to control flow of accumulated solids through said siphon means, first control means responsive to fluid pressure in said teeter column to activate said dilution liquid supply mean and said siphon flow controlling means to induce flow in said siphon means, and second control means responsive to excessive pressure at the peak of said siphon to activate said prime liquid supply means, said first and said second control means being interconnected to permit said prime liquid supply means to be activated only if said dilution liquid supply means and said siphon flow controlling means are activated.

2. Hydraulic classifying apparatus comprising: a tank, means supplying solids to said tank to be classified, means providing a teeter column in said tank for receiving and Classifying the solids according to settling rate, said latter means including liquid introduction means adjacent the base of the teeter column to provide an upward flow of liquid in the teeter column to accumulate solids of predetermined settling characteristic near the base of the teeter column, siphon means opening near the base "of the column to withdraw the accumulated solids, means supplying dilution liquid to said siphon means to facilitate the siphoning of the solids, control means operatively connected to be responsive to the density of solids in the teeter column, said control means being interconnected with said dilution liquid supply means so that said dilution liquid supply means is inoperative and does not supply dilution liquid to said siphon means when the density of solids in the teeter column is below a predetermined minimum, valve means in said siphon means to control the siphonic fi-ow therein by constricting the cross-sectional flow area of said siphon means, said density responsive control means being operatively interconnected with said siphon flow control means to allow flow of solids through said siphon means when the density of the teeter column is above a predetermined minimum.

3. Hydraulic classifying apparatus comprising: a tank, means supplying solids to be classified into the upper portion of said tank, constriction means in the lower portion of said tank, means for providing a teeter column between said solids supply means and said constriction means including means supplying a liquid into the lower portion of said tank below said constriction means and providing an upward flow of liquid through said constriction means and the teeter column to accumulate solids of predetermined settling rate adjacent said constriction means, siphon means extending to a point adjacent said constriction means to withdraw the accumulated solids, controllable means to supply prime liquid to said siphon means, first control means responsive to an excess pressure in the peak of said siphon means to actuate said controllable means to supply prime liquid to said siphon means, and second control means operatively interconnected with said first control means to prevent siphon priming when the density of said teeter column adjacent the constriction means is below a predetermined value.

References Cited by the Examiner UNITED STATES PATENTS 301,391 7/1884 Reinecke 137-142 X 2,714,958 8/1955 Evans 209158 2,877,896 3/1959 Jones 209-1725 3,224,581 12/1965 McKnight 209158 FRANK W. LUTTER, Primary Examiner.

S. B. WILLIAMS, Assistant Examiner. 

2. HYDRAULIC CLASSIFYING APPARATUS COMPRISING: A TANK, MEANS SUPPLYING SOLIDS TO SAID TANK TO BE CLASSIFIED, MEANS PROVIDING A TEETER COLUMN IN SAID TANK FOR RECEIVING AND CLASSIFYING THE SOLIDS ACCORDING TO SETTLING RATE, SAID LATTER MEANS INCLUDING LIQUID INTRODUCTION MEANS ADJACENT THE BASE OF THE TEETER COLUMN TO PROVIDE AN UPWARD FLOW OF LIQUID IN THE TEETER COLUMN TO ACCUMULATE SOLIDS OF PREDETERMINED SETTLING CHARACTERISTICS NEAR THE BASE OF THE TEETER COLUMN, SIPHON MEANS OPENING NEAR THE BASE OF THE COLUMN TO WITHDRAW THE ACCUMULATED SOLIDS, MEANS SUPPLYING DILUTION LIQUID TO SAID SIPHON MEANS TO FACILITATE THE SIPHONING OF THE SOLIDS, CONTROL MEANS OPERATIVELY CONNECTED TO BE RESPONSIVE TO THE DENSITY OF SOLIDS IN 